I wanted to use kill --verbose ... in a bash script but I got the error kill: -verbose: invalid signal specification. This was weird as it worked fine in fish. My investigation has lead me to this weird behaviour:

$ which kill
$ sleep 5 & kill --verbose $!
[1] 33730
bash: kill: -verbose: invalid signal specification
... wait for sleep to finish ... 
[1]+  Done                    sleep 5
$ sleep 5 & /usr/bin/kill --verbose $!
[1] 33964
sending signal 15 to pid 33964
[1]+  Terminated              sleep 5

What is going on? Why does kill not recognise the --verbose flag, but /usr/bin/kill does, when which kill == /usr/bin/kill?

1 Answer 1


which is misleading; try type instead:

$ type kill
kill is a shell builtin

When you run kill, bash uses its built-in command, which doesn’t recognise --verbose. When you specify the full path, the external command /usr/bin/kill is run instead, and that does support --verbose (in your case).

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